Increasing oil production and decreasing water production of wells



Deg 26, 1944. M. WILLIAMS INCREASING OIL PRODUCTION AND DEGREASING WATERPRODUCTiON OF A WELL Fil ed April 8 1938 Zz/JLMW INVENTOR.

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scribed, preferentially oil wettable. borehole above the gravel is acasing 6 which is held in place by cement I and which has a PatentedDec. 26, 1944 UNITED STATES PATENT OFFICE 2,366,078 INCREASING QOILPRODUCTION AND DE- CREASIN G WELLS WATER; PRODUCTION OF ration ofDelaware Application' April s; 1938, Serial No. 200,9o2

(Cl. lee-2c) 14 Claims.

The present invention is directed to the treatment of oil sands for thepurpose of increasing oil flow and retarding the flow of water, and

to a product to be used in such treatment.

It has already been proposed to treat oil sands, by enlarging the cavityin the sand by under reaming and to fill the enlarged cavity so formedwith gravel. Such treatment increases the flow of oil from the sandbecause it increases the amount of exposed surface of oil sand andminimizes or wholly eliminates the plugging up of the outlet from theformation by loose sand resulting from caveins or other types ofapparatus and procedure which have been proposed for this treatment ofoil sands,

disintegration of the formation. The various which is known asgravelling, are discussed in formation is enlarged to form a cavity 4which is filled with gravel or other granular material 5 which is, ashereinafter more specifically decasing head 8 provided with an inletpipe 9.

concentrically arranged in the casing is a'tubing,

ID the lower end of which terminates in a perforated section and theupper endof which is connected to a pipe lineby a connection l2.

In the above described arrangement the cecented casing and the tubingare conventional parts that are set in place in the completion of an oilwell. The gravel is thereafter introduoed .by anyone of a number ofknown means 3 and may be fed in through pipe 9 directlywhere andflllsthe cavity. A bed of gravel surrounds the perforated section II ofthe tubing and prevents the s ding of the tubing as well as increasingthe rate .of production. According to the present invention, an additional benefit is derived from gravelling by utilizing a-granularmaterial coated with a water insoluble substance having an amnity foroil as Set in theproducing formation. Theuse of this packingmaterial-facilitates the flow of 7 oil from the formation to the outletand at the same time retards the flow of water, thereby. imparting tothe particular well treated an increased oilwater ratio that is notattainable by the use of uncoated granular material.

In general, a suitable coating material, according to the presentinvention, is a water insoluble substance-preferably non-crystalline in.character, which is capable of dissolving or beingcolloidally dispersedin oil.

Examples of suitable coating materials are soaps of metals other thanthe alkali metals which, in general, are water insoluble. Such soaps maybe derived from organic compounds of the most varied character,including sulphuric acid derivatives of open chain and closed chainhydrocarbonssuch as mineral oil sulfonic acids, fatty acids of bothanimal and. vegetable acids, ireto acids, naphthenic acids, hydroxyacids. and the like.

The most suitable coating materials for the purpose of the presentinvention are the heavy metal soaps of fatty acids and particularly ofunsaturated fatty acids. It has been found that lead oleate, forexample, is capable of forming an extraordinarily strong bond withsiliceous materials, so strong in fact as to give rise to the assumptionthat it is of a molecular nature.

Dry gravel, when treated with a solution or colloidal dispersion of leadoleate, receives a coating which is resistant to practically all commontypes of chemical treatment. A similar result is obtained when otherheavy metal soaps of unsaturated fatty acids .are employed. The coatingsso formed appear to resist even those liquids in which theywere solublebefore being applied to the gravel, thereby strengtheningthe conclusionthat some sort of chemical union between the gravel and the soap occurs.

A suitable method for coating the gravel or other granular material withan oil wettable agent of the general character described above is toimmerse the gravel in'for spray it with a, solution or colloidaldispersion of the treating agent in a hydrocarbon solvent such askerosene or naphtha. In order to'secure the strong bond between thegranular material and the coating agent it is extremelydesirable thatthe granular material be dry. Any moisture in the granular material oron its surface will weaken the bond between the coatingand the granularmaterial. For this reason it is preferable to the packing for theenlarged cavity in the Oil coat the granular-material before'it isadmixed with the fluid, usually an aqueous mud, which is employed as acarrying medium for depositing the granular material in the enlargedcavity in the oil bearing formation. It is to be.understood, however,that the benefits inherent in the use of coated granular material,accordingto the present invention, can be secured in part by treatingthe granular material in place in the enlarged cavity.- Some improvementis noticeable when the coating material is added in a finely dividedstate to the mud employed for depositing the granular material in theformation. The results obtained by this pro-,

cedure, however, are not uniform or reliable.

For satisfactory results it is preferable to em-' ploy a solutionor'dispersion of coating agent ranging in strength from about 0.5% toalthough higher concentrations can be employed without any detrimentaleffect. When the higher concentrations are employed it is advantageousto include in the composition some free acid, the salt of which isemployed.

the surface end of said conduit a granular m'aterial coated with anagent more readily wettable by oil than. by water.

When the immersion method is employed the best. results are obtained bykeeping the granular material immersed in the solution of the coatingagent for an extended period, ranging from one to several hours.Whenspraying or immersion is the coating method employed, it ispreferable to use a solvent of high volatility.

When' it is desired towtreat -the granular material in situ, it ispermissible to use heavier solvents such as gas oil or even crude oil. I

As is known, the granular material will generally vary in size fromabout A of an inch in diameter to about 1 inch in diameter, although Igranular material as small as 60 mesh may be employed. Gravel is thecustomary granular material employed, butother materials such asgranulated blast furnace slag and granulated minerals of siliceous typecan be used.

In the above description reference has been made to the use of aqueousmud as a carrying medium for conveying the, granular material from thesurface to the cavity in the oil bearing formation. Also contemplated isthe use of oil ,as a carrying medium for this purpose.

The nature and objects of the present in- 5. A method for producing oilfrom an oil bearing formation which comprises establishinga conduitbetween said formation and the surface and interposing between theformation and the surface'end of said conduit a granular material coatedwith a water insoluble soap.

6. A method according to claim 5 in which the water insoluble soap is aheavy metal soap of an unsaturated fatty acid. I

'7. The method of completing an oil well having a perforated well screenwhich comprises placing in the well at the producing zone a filter packof a granular,aoil-wettable,- waterrepellent material of a size suchthat the interstitial spaces are of capillary dimensions.

8. The method of completing an oil well having a perforated well screenin a cavity in the oil producing zone, which comprises filling saidcavity about" the screen with an aggregate of a subdivided oil-wettable,water-repellent material the particles of which have a size betweentwenty and sixty mesh.

9. The method of increasing the ratio of oil to water in theproduction-of an oil well which comprises placing and maintaining in thewell at a predetermined depth a pack of particles of subdivided materialthe. surface of which is capable of being wet by oil but which isrepellent to water, the interstitial spaces of the pack being ofcapillary size. I I

10. The method of increasing the production of oil from a well withrespect to the amount of water produced from the well, which comprisesplacing and maintaining in 'said well in the .producing zone a body ofgravel-like material of from twenty to sixty mesh, the surfaces of saidmaterial beingoil-wettable but water-repellent so that oil will flowreadily through the interstices in said body while water will be heldback due to the increased adhesion tension of the material for oiland'the decreased adhesion tension of the material for water.

* 11. The method of increasing the ratio of oil I i to Water in theproduction of an oil well which vention having been thus described, whatis claimed as new and useful and is desired to be secured by LettersPatent is? l. A method for producing oil from an oil bearing formationwhich comprises establish- I ing a conduit between the formation andthesurface and interposing between the inlet end of the'conduit and theformation a granular material coated with an agent more readily wettableby oil than by water.

2. A method for producing oil from an oil bearing formation whichcomprises establishing a conduit between .the formation and the surface,forming an' enlarged cavity in the formation adjacent the inlet end ofsaid conduit and filling said cavity with a granular material coatedwith a water insoluble soap.

3. A method for producing oil from an oil' bearing formation whichcomprises establishing a conduit between the formation and the surfaceand interposing between the inlet end of the conduit and the formation agranular material coated with a heavy metal soap of an unsaturated fattyacid. I

4. A method. for producing oil from anoil bearing formation whichcomprises establishing a conduit between the formation and the sur-.

face and interposing between the formation and comprises treatinggravel-like material with a substance capable of rendering the'surfacesof said material oil-wettable and water-repellentand then placing saidtreated material in the well cavity in theproducing zone so that oil canenter the well through theinterstices in the material while the passageof water through said interstices will be retarded.

12. The method of increasing the ratio of oil to water in the productionof an oil well which.

comprises placing a bedof a gravel-like material in'the cavity of thewell formed in the producing oil sands and then treating'said gravellikematerial and the oil sands in the-vicinity of the well cavity witha-substance capable of rendering the gravel-like material and the oilsands oil-wettable and water-repellent;

13. -A filter pack of a granular material whose surfaces are water andoil insoluble and which.

I have the property of remaining oil-wettable and water-repellent in thepresence of both oil and water, the-particles of said material having asize' between twenty and sixty mesh.

14'. A packing material for an oil-bearing formation comprising a.granular material coated with a. heavy metal soap of an unsaturatedfatty acid. MTLTON WILLIAMS.

